Cap and shell fastening



March 3, @311.

c. E. ANDERSON CAP ANDSHELL FASTENING Filed April 5, 1923 M mg. I

11v VENTOR CARL ER/c fl/vnERs 0M ATTORNEYj Patented Mar. 3, 1931 UNITED STATES PATENT OFFICE."

CARL ERIC ANDERSON, OF STRATFORD, CONNECTICUT, ASSIGNOR TO THE BRYANT ELECTRIC COMPANY, OF BRIDGEPORT,

NEGTICUT My invention relates to capand shell fastenings, and particularly to a fastening of a type suitable for detachably securing together the cap and shell elements of an electric socket casing. The object of my inven tion is to provide an improved construction of the latching devices.

In the accompanying draw1ngs Fig. 1 is a broken side elevation of a cap .element for asocket casing;

Fig. 2 is a similar View showing the cap and shell in latching relation;

Fig. 3 is a perspective of the shell element;

Fig. 4 is an enlarged section on the line H, Fig. 2; and

Fig. 5 is a section on the line 55, Fig. 4.

While the invention is illustrated in connection with the separable cap and shell elements of a standard electric lamp socket casing, it is obviously applicable to the separable casing elements of a pendant switch, or the like, or fittingsof the type illustrated in the patent to Goodridge No. 977,297. It is further obvious that modifications in detail of shape and arrangement of the latching elements may be readily made by those skilled in the art, without departing from what I claim as my invention.

As here shown the casing comprises a cap 6 and shell 7 adapted to telescopically interfit, and provided within the telescoping area with the latching elements to which my invention particularly relates.

The latching elements of the cap are formed by an annular series of dogs 8,\struck inwardly from the otherwise plain cap flange 9 and having their cut engaging edges 10 faced away from the shell and their projecting sides rounded and beveled towards the margin of the flange. A finishing ring 11 (Fig. 5) may be provided to surround the flange 9, and having its upper and lower margins 12 and 13 inwardly oflset respectively I above the shoulder 14 of the cap, and the lower margin of the flange 9.

To cooperate with the dogs 8, the shell 7 is provided within its sleeving area with an annular series of apertures 15 adapted to receive the dogs 8 ofthe cap flange. The majority of the apertures 15. have in register CONNECTICUT, A CORPORATION OF CON- Application filed April 5, 1923. Serial No. 630,098. I

therewith longitudinal grooves 16 leading to sembled condition.

To prevent endwise separation of the cap andshell, the grooves 16 are omitted at certain portions of the shell aligned with certain of the apertures; thus, in the construction shown the grooves are omitted at the points aligned with the apertures 17, 18 and 19. The apertures 17 is adjacent the slot 20 in the shell provided for the reception of the usual switch key for the socket body (not shown), while the apertures 18 and 19 are arranged in the neighborhood of a point substantially diametrically opposite the aperture 17. The edges 21 01? the apertures 17, 18 and 19 adjacent the sleeving end of the shell thus form detaining catches which cooperate with the opposed edges 10 of the inwardly struck dogs 8 of the cap and prevent endwise separation of the parts in latching position. Notches 22 may be formed in the margin of the shell in alignment with the apertures 17 18 and 19 to facilitate the entry of and to guide the cooperating dogs 8 into these apertures. Inasmuch as the spacing of the dogs 8 around the periphery of the flange 9 corresponds to the spacing of the apertures in the sleeving area of the shell, it is obvious that the 'parts may be latched together in any relative rotary position.

The operation of the latching devices is readily understood. Assuming the cap to be secured in fixed position upon the wire conduit, the shell 7 is telescopically inserted into the cap flange until halted by the shoulder 14. As it enters the flange the beveled sides of certain of the dogs 8 engage the notches 22 in the margin of the shell and ride over the undeformed portions of the latter in register with the apertures 17, 18 and 19. The inherent resiliency of the shell enables the latter to contract sufl'iciently to ride over the inwardly projecting dogs 8 of the cap, followed, when the shell is shoved fully home, by its automatic expansion to normal condition, whereupon the edges 21 of the apertures 17 18 and 19 pass over the retaining edges 10 of the dogs. The latter thus snap into the holes 17 18 and 19 and engage the margins thereof, thus preventing endwise separation of the parts. The lateral engagement of the dogs in the holes 15 serves to prevent relative rotation of the parts.

In order to free the shell from the cap it is merely necessary to press the latter-in- 'ward in the area adjacent the aperture 17 thus moving the margin 21 of the aperture zlgbll to oppose relative rotation of the cap d shell when assembled. In testimony whereof I have signed my V name to this s out of engagement with the edge '10 of the dog 8 which enters the aperture, whereupon the shell may be rocked free of the cap in a manner well understood invthe art.

Various modifications will readily occur to those dealing with the problem. a For. instance, only the apertures17, 18 and 19 are essential to the operation of the latching mechanism. The remaining apertures may be omitted, being substituted by continuations of the guide channels 16; I prefer the apertures, however, since a more satisfactory engagement with the sides of the dogs 8 is 'afiorded by the edges thereof than by the curved sides of the channels 16. On the other hand, the apertures 15 may be continued to the margin of the shell; but this construction is not desirable since it too seriously.

weakens the structure at this point. As above stated, the notches 22 may be omitted, since they serve merely to facilitate the entry of and to locate the dogs with respect to the apertures 17. 18 and19, the location being sufficiently effected by the channels 16. The sides of adiacentvcha nnels 16 may be flared toward each other as they, approach the margin of the shell in order to more perfectly guide the dogs into the apertures 17 18 and 19, but this is not a matter of practical necessity since the V-shaped sides of the dogs themselves serve this function.

I claim as my invention- A cap and shell fastening to be engaged by an endwise telescopic movement and comprising a cap with a plain annular flange having aseries of dogs 8 struck inwardly with engaging cut edges 10 faced away from the shell,-the faces and sides of the dogs being rounded and beveled towards the rim of the cap flange in combination with a shell having longitudinal grooves 16 at the solid margin of its rim and having apertures with edges 21 to cooperate with the engaging edges 10 of the dogs on the cap, to oppose endwise detachment of the cap, the sides of the dogs engaging corresponding shoulders on the cification. 

